Human actions, such as sleeping postures and turning over in bed with pillows, are consistent according to human engineering and physiology. The desire for humans to form their bodies into natural and comfortable posture according to their body shape has led to the use of pillows. However, very little scientific research on the subject of pillows has been conducted. Generally speaking, most pillows are simply made out of a containment holder or bag in the form of a pillow filled with a variety of soft media.
Recent studies suggest the use of neck-bones' support pillows since supporting neck bones brings good physiological results in breathing and blood circulation. However, it is difficult for humans to obtain sound sleep by means of supporting neck bones alone when one sleeps in supine and side-orientated sleeping positions.